WORKSHOP - 3D Swirling Flow Through an Orifice Plate

Polar Co-ordinates, Cyclic Boundary Conditions

This example shows how to set up and run the simulation of a swirling
flow through an orifice plate using VR in cylindrical-polar coordinates.

The flow is three-dimensional and its geometry is shown below. Velocity and
pressure will be solved. Cyclic boundary conditions are used to allow the flow to swirl.

At the inlet, the flow velocity is 1 m/s axially, swirling at 20 radians/s.

As a second exercise, a flow-straightener is introduced down-stream of the orifice in order to remove the swirl component.

Accessing PHOENICS-VR.

From the system level:

To enter the PHOENICS-VR environment, click on the PHOENICS icon on the
desktop, or click on Start, programs, PHOENICS, PHOENICS.

From the commander level:

To enter the PHOENICS-VR environment, click on the 'Run vre' icon in the
left column.

In PHOENICS-VR environment,

Start with an 'empty' case - click on 'File' then on 'Start New
Case', then on 'Core', then click on 'OK'; to confirm the
resetting.

To enter VR Editor:

This is the default mode of operation.

Within VR Editor.

Set the domain size, and activate solution of variables:

Click on 'Main Menu' and set 'Swirling Flow Through an Orifice Plate'
as the Title.

Click on 'Geometry'.

Click on Co-ordinate system 'Cartesian', and select 'Cylindrical-polar'. In
Cylindrical-polar co-ordinates, X is always the angle, measured in radians, Y is always
the radius in metres, and Z is always the axis, also in metres.

Change the X-Domain Size to 6.28319 radians (2 PI).

Change the Y-Domain size to 0.2 m.

Leave the Z-Domain Size at 1.0 m.

Set the number of cells:

20 cells in the X-direction,

15 cells in the Y-direction,

15 cells in the Z-direction.

Click 'OK' to close the Grid mesh settings dialog.

Click on 'Sources'. Click on 'Velocity' next to 'U values are', and select
'Angular Velocity'. From now on, all references to U velocity inlet and initial values are
interpreted as radians per second.

Click on 'All slabs off' next to 'Cyclic boundaries', and select 'All slabs on'. This
allows fluid to pass freely through the boundaries at X=0 and X=Xmax.

Click on 'Top menu' and then on 'OK'.

Click 'Reset' on the Movement control panel, then 'Fit to window' to re-scale the view to
fit the geometry. Use the movement control buttons to get a view similar to that shown at
the start of the tutorial.